Kara Rogers is the senior editor of biomedical sciences at Encyclopædia Britannica. She holds a Ph.D. in pharmacology and toxicology from the University of Arizona.

Rogers writes for various publications on topics ranging from medicine and genetics to animals and nature. She is the author of Out of Nature: Why Drugs from Plants Matter to the Future of Humanity (The University of Arizona Press, 2012) and The Quiet Extinction: Stories of North America's Rare and Threatened Plants (The University of Arizona Press, 2015). Rogers is a member of the National Association of Science Writers.

psychological or psychophysiological improvement attributed to therapy with an inert substance or a simulated (sham) procedure. There is no clear explanation for why some persons experience measurable improvement when given an inert substance for treatment. Research has indicated that the effect may be caused by the person’s expectations about the treatment rather than being a direct effect of the treatment itself. One of the first doctors to deliberately prescribe placebos, or inert treatments, was Scottish physician William Cullen, who mentioned in a lecture series in 1772 having given placebos to patients to appease them, not to cure their conditions. Despite Cullen’s observations that placebos appeared to produce beneficial effects in some patients, the term placebo effect was not introduced into medicine until the early 20th century. In modern medicine, placebos, including inert drugs and sham procedures, are frequently used in clinical trials that are designed to test new...

A single cell can be a self-sustaining organism or one of trillions in a larger life form. Though visible only with the help of a microscope, cells are highly structured entities that perform a myriad of functions in every living thing and store critical genetic information. This fascinating volume examines the organization of various types of cells and provides an in-depth look at how cells operate alone to generate new cells and act as part of a larger network with others.

About half of all species under threat of extinction in the world today are plants. The loss of plant biodiversity is disturbing for many reasons, but especially because it is a reflection of the growing disconnect between humans and nature. Plants have been used for millennia in traditional systems of healing and have held a significant place in drug development for Western medicine as well. Despite the recent dominance of synthetic drug production, natural product discovery remains the backbone...

The development and evolution of all species can, in many ways, be traced to a few biochemical reactions that facilitate metabolic and/or photosynthetic changes in each life form. Indeed, advances in the field of biochemistry have intimately depended on the study of these processes and the way basic molecules fragment and synthesize to produce elements vital to the survival of each organism. This insightful volume considers the various types, causes, and results of different reactions that operate...

In the United States and Canada, thousands of species of native plants are edging toward the brink of extinction, and they are doing so quietly. They are slipping away inconspicuously from settings as diverse as backyards and protected lands. The factors that have contributed to their disappearance are varied and complex, but the consequences of their loss are immeasurable.With extensive histories of a cast of familiar and rare North American plants,
The Quiet Extinction...